Popular science knowledge suitable for primary school students

Popular science knowledge suitable for primary school students is as follows:

1. How many solar terms are there in the China lunar calendar? (24)

2. What is the name of a technology called length unit that has been talked about by people in recent years? (nanotechnology)

3. How is the sound generated? (Vibration of air)

4. What are the main causes of seawater tides? (lunar gravity)

According to the law of China, a citizen under a few years old is called a minor? ( 18)

6. Are penguins endemic to Antarctica or the Arctic? (Antarctic)

7. When did Hong Kong return to the motherland? (1 July 9971)

There are four oceans on the earth. What ocean is located in the northernmost part of the earth? (Arctic Ocean)

9. Who was the national hero who banned opium in Humen during Daoguang period of Qing Dynasty? (Lin Zexu)

10. What kind of plants are you talking about? Can you give it another name? (Lotus, Lotus, Hibiscus, Lotus)

1 1. Who is the hero of the story of "joining the army instead of father" in China history? (Mulan)

12, what is the "five elements" in China ancient culture? (wood, fire, water, earth)

13, which star is the closest to the earth? (Sun)

"Spring silkworms will always spin silk to death", and a silkworm can spin silk to make cocoons. What leaves does she eat? (Mulberry)